Venkatesh K, Roe R M, Apperson C S, Sonenshine D E, Schriefer M E, Boland L M
Department of Entomology, North Carolina State University, Raleigh 27695.
J Med Entomol. 1990 Jan;27(1):36-42. doi: 10.1093/jmedent/27.1.36.
Juvenile hormone (JH)-I and -III were used as model substrates to study the in vitro metabolism of JH in the hemolymph and body homogenates of the American dog tick, Dermacentor variabilis (Say). Ester hydrolysis was the principal pathway of JH metabolism in hemolymph and homogenates. JH also was converted into JH-diol primarily by body homogenates, indicating the presence of JH epoxide hydrolase activity. JH epoxide hydrolase activity, alpha-naphthyl acetate esterase activity, and protein concentration per milligram wet weight were significantly lower (t test, alpha = 0.05) in homogenates of partially fed, virgin and replete, mated females of D. variabilis compared with unfed, virgin females. The decline in these factors was probably because of the influx of water into the tissues caused by the blood meal. In addition, the epoxide hydrolase and alpha-naphthyl acetate esterase activity per milligram tissue protein decreased significantly during this time. Mating of fed females rather than feeding alone caused a significant decline in the tissue JH esterase activity per milligram wet weight but not per milligram protein. The JH esterase activity per milligram protein was significantly higher in partially fed, virgin and replete, mated females compared with unfed females, indicating that feeding may actually increase JH esterase activity on a protein basis. JH-III was metabolized 1.4 times faster than JH-I by the hemolymph of partially fed, virgin females. The inhibitors O,O-diisopropyl phosphorofluoridate and octylthio-1,1,1-trifluoropropan-2-one at 10(-4) M inhibited JH and alpha-naphthyl acetate esterase activity in hemolymph and body homogenate.
保幼激素（JH）-I和-III被用作模型底物，以研究美洲犬蜱（Dermacentor variabilis (Say)）血淋巴和身体匀浆中JH的体外代谢。酯水解是血淋巴和匀浆中JH代谢的主要途径。JH还主要被身体匀浆转化为JH-二醇，表明存在JH环氧水解酶活性。与未进食的未交配雌性相比，美洲犬蜱部分进食、未交配且饱血、已交配雌性的匀浆中，JH环氧水解酶活性、α-萘乙酸酯酶活性和每毫克湿重的蛋白质浓度显著降低（t检验，α = 0.05）。这些因素的下降可能是由于血餐导致水分流入组织。此外，在此期间每毫克组织蛋白的环氧水解酶和α-萘乙酸酯酶活性显著降低。已进食雌性的交配而非单独进食导致每毫克湿重的组织JH酯酶活性显著下降，但每毫克蛋白质的活性未下降。与未进食雌性相比，部分进食、未交配且饱血、已交配雌性每毫克蛋白质的JH酯酶活性显著更高，表明进食实际上可能在蛋白质基础上增加JH酯酶活性。部分进食、未交配雌性的血淋巴对JH-III的代谢速度比对JH-I快1.4倍。10^(-4) M的抑制剂氟磷酸二异丙酯和辛硫基-1,1,1-三氟-2-丙酮抑制血淋巴和身体匀浆中的JH和α-萘乙酸酯酶活性。
